Inadequate intake causes oliguria and adequate hydration is sufficient. Low urine due to kidney failure is then mainly focused on kidney protection. If you need to consider whether the patient is hyperkalemic, take a potassium-depleting diuretic for high potassium; for hypokalemic oliguria, take a potassium-preserving diuretic, such as aminoglutethimide. For low urine and hypoproteinemia, protein supplements are needed. Those with hypertensive oedema can be treated with aminoglutethimide, aminopterin and tachyphylaxis.